Field of the earth wave over long inhomogeneous radio paths

Abstract

High-precision radio systems use the properties of the propagation of an electromagnetic field along the Earth's surface. Nowadays the interest remains in the methods for calculating the amplitude-phase structure of the field over real radio paths. The main property of the earthwave field is the stability of the phase structure and diffraction propagation over relatively large distances. The field of the earthwave is considered which is created by a vertical electric dipole over an electrically and geometrically inhomogeneous surface of the Earth. Such waves are called diurnal, they are of interest at distances when the influence of waves reflected from the ionosphere on the field can be neglected. In the case of an electrically homogeneous radio path, the attenuation function of the earthwave field is calculated using the Sommerfeld’s formulas for the flat surface model and the Fock’s series for the spherical surface model. To calculate the levels of the electromagnetic field and its phase over geometrically and electrically inhomogeneous radio paths, the most used method is the numerical solution of the Hufford’s integral equation. The disadvantage of numerically integrating the Hufford equation is that the range of applicability of the method is limited in distance due to the loss of accuracy of calculations. In practice, such a disadvantage is at high frequencies with "poor" conductivities of the underlying medium. For extended radio paths, it is proposed to use the method of the modernized Feinberg’s integral equation for electrically inhomogeneous radio paths taking into account the relief of the terrain to calculate the function of attenuation of the earthwave field. This method allows performing calculations in the LF-MF ranges of radio waves over paths with relatively "poor" conductivity.

• поле земной волны
• поверхностный импеданс
• функция ослабления
• рельеф радиотрассы
• earthwave field
• surface impedance
• attenuation function
• radio path relief

For citation

References

1. Фок В.А. Проблемы дифракции и распространения электромагнитных волн. - М.: Сов. радио, 1970. 517 с.
2. Wait J.R. Electromagnetic waves in stratified media. - New York: Pergamon Press Inc, 1962. 372 p.
3. Фейнберг Е.Л. Распространение радиоволн вдоль земной поверхности. - М.: Физматлит, 1999. 496 с.
4. Макаров Г.И., Новиков В.В., Рыбачек С.Т. Распространение электромагнитных волн над земной поверхностью. - М.: Наука, 1991. 196 с.
5. Hufford G.A. An integral equation approach to the problem of wave propagation over an irregular surface // Quarterly of Applied Mathematics. 1952. Vol. 9. p. 391-404.
6. Проскурин Е.П., Пылаев А.А., Тихомиров Н.П., Штейнберг А.А. Распространение радиоволн над электрически и геометрически неоднородными трассами // Проблемы дифракции и распространения волн. -Л.: Изд-во ЛГУ, 1981. Вып. 18. с. 171-183.
7. Горшенев А.М., Тихомиров Н.П. Численное решение уравнения Фейнберга для функции ослабления на электрически неоднородных трассах // Тезисы докладов Межведомственного семинара по распространению километровых и более длинных радиоволн. Хабаровск, 1983. с. 39-40.
8. Башкуев Ю.Б., Хаптанов В.Б., Дембелов М.Г. Экспериментальное доказательство существования поверхностной электромагнитной волны // Письма в ЖТФ. 2010. Т. 36, № 3. с. 88-95.
9. Дембелов М.Г., Башкуев Ю.Б. Моделирование распространения длинных и средних радиоволн в гористой местности // Электромагнитные волны и электронные системы. 2005. Т. 10, № 4. с. 11-15.